Apparatus and methods for treating stroke and controlling cerebral flow characteristics

ABSTRACT

Apparatus and methods for treatment of stroke are provided. In a preferred embodiment, the present invention disposes at least one catheter having a distal occlusive member in either the common carotid artery (CCA) or both the vertebral artery (VA) and the CCA on the hemisphere of the cerebral occlusion. Blood flow in the opposing carotid and/or vertebral arteries may be inhibited. Retrograde or antegrade flow may be provided through either catheter independently to effectively control cerebral flow characteristics. Under such controlled flow conditions, a thrombectomy device may be used to treat the occlusion, and any emboli generated are directed into the catheter(s).

RELATED APPLICATIONS

The present application is a divisional of copending U.S. patentapplication Ser. No. 09/972,225, filed Oct. 4, 2001.

FIELD OF THE INVENTION

The present invention relates to improved apparatus and methods fortreatment of stroke. More specifically, the apparatus and methods of thepresent invention are directed to treating stroke by controllingcerebral blood flow and removing thrombi and/or emboli.

BACKGROUND OF THE INVENTION

Cerebral occlusions that lead to stroke require swift and effectivetherapy to reduce morbidity and mortality rates associated with thedisease. Many current technologies for treating stroke are inadequatebecause emboli generated during the procedure may travel downstream fromthe original occlusion and cause ischemia. There is currently a need fora stroke treatment system that provides a swift and efficient treatmentfor occlusions while simultaneously controlling cerebral flowcharacteristics.

In the initial stages of stroke, a CT scan or MRI may be used todiagnose the cerebral occlusion, which commonly occurs in the middlecerebral arteries. Many current technologies position a catheterproximal to the occlusion, then deliver clot dissolving drugs to treatthe lesion. A drawback associated with such technology is thatdelivering drugs may require a period of up to six hours to adequatelytreat the occlusion. Another drawback associated with lytic agents(i.e., clot dissolving agents) is that they often facilitate bleeding.

When removing thrombus using mechanical embolectomy devices, it isbeneficial to engage the thrombus and remove it as cleanly as possible,to reduce the amount of emboli that are liberated. However, in the eventthat emboli are generated during mechanical disruption of the thrombus,it is imperative that they be subsequently removed from the vasculature.

Many current drug delivery and mechanical treatment methods areperformed under antegrade flow conditions. Such treatment methods do notattempt to manipulate flow characteristics in the cerebral vasculature,e.g, the Circle of Willis and communicating vessels, such that embolimay be removed. Accordingly, there remains a need to provide effectivethrombus and emboli removal from the cerebral vasculature whilesimultaneously controlling flow within that vasculature.

U.S. Pat. No. 6,161,547 to Barbut (Barbut '547) describes a techniquefor enhancing flow in the cerebral vasculature in treating patients withacute stroke or other cerebrovascular disease. The technique involves:(1) positioning a first tubular member in a vascular location suitablefor receiving antegrade blood flow; (2) positioning a second tubularmember in a contralateral artery of the occlusion (e.g., for anocclusion located in the left common carotid artery the second tubularmember is placed in the right common carotid artery); and coupling thefirst tubular member to the second tubular member using a pump andfilter.

The first tubular member receives antegrade blood flow and channels theblood to the pump and filter, where the blood then is reperfused via thesecond tubular member into the contralateral artery, thus increasingblood flow to the opposing hemisphere of the brain. The first and secondtubular members may include balloons disposed adjacent to their distalends.

The techniques described in the foregoing patent have several drawbacks.For example, if the first balloon of the first tubular member isdeployed in the left common carotid artery, as shown in FIG. 7C,aspiration of blood from the vessel between the balloon and theocclusion may cause the vessel to collapse. On the other hand, if theballoon is not deployed, failure to stabilize the distal tip may resultin damage to the vessel walls. In addition, failure to occlude thevessel may permit antegrade blood flow to diverted into that apparatus,rather than blood distal to the first tubular member.

The Barbut '547 patent further discloses that inflating the balloon ofthe second tubular member may assist in controlling the flow to thecontralateral artery or provide more efficient administration ofpharmacotherapy to the cerebral tissues. However, when that balloon isdeployed, the contralateral artery may be starved of sufficient flow,since the only other flow in that artery is that aspirated through thefirst tubular member. On the other hand, if the balloon of the secondtubular member is not inflated, no flow control is possible.

A method for removing cerebral occlusions is described in U.S. Pat. No.6,165,199 to Barbut (Barbut '199). This patent describes a catheterhaving an aspiration port at its distal end that communicates with avacuum at its proximal end. A perfusion port disposed in a lateralsurface of the catheter may be used to enhance antegrade flow incollateral arteries. In use, the aspiration port is positioned proximalto an occlusion to provide a direct suction effect on the occlusion. Theperfused flow in collateral arteries is intended to augment retrogradeflow distal to the occlusion, such that the occlusion is dislodged viathe pressure and directed toward the aspiration port. A choppingmechanism, e.g., an abrasive grinding surface or a rotatable blade,coupled to the aspiration port recognizes when the aspiration port isclogged. The chopping mechanism then engages to break up the occlusionand permit it to enter the aspiration port in smaller pieces.

The device described in the Barbut '199 patent has severaldisadvantages. First, the use of a vacuum to aspirate the occlusionrequires an external pressure monitoring device. The application of toomuch vacuum pressure through the aspiration port may cause trauma, i.e.,collapse, to the vessel wall. Also, because the system is intended todislodge the occlusion using a pressure differential, a choppingmechanism is required to prevent the entire mass from clogging theaspiration port. The use of a chopping mechanism, however, may generatesuch a large quantity of emboli that it may be difficult to retrieve allof the emboli. In addition, emboli generated by the action of thechopping mechanism may accumulate alongside the catheter, between theaspiration port and the distal balloon. Once this occurs, it is unclearhow the emboli will be removed.

Yet another drawback of the device described in the Barbut '199 patentis that high-pressure perfusion in collateral arteries may not augmentretrograde flow distal to the occlusion as hypothesized. The patentindicates that high-pressure perfusion in collateral arteries via sideports in the catheter may be sufficient to cause an increase in pressuredistal to the occlusion. Antegrade blood flow from the heart inunaffected arteries, e.g., other vertebral and/or carotid arteries, maymake it difficult for the pressure differential induced in thecontralateral arteries to be communicated back to the occluded artery ina retrograde fashion.

Other methods for treating ischemic brain stroke have involved cerebralretroperfusion techniques. U.S. Pat. No. 5,794,629 to Frazee describes amethod that comprises at least partially occluding the first and secondtransverse venous sinuses and introducing a flow of the patient'sarterial blood to a location distal to the partial venous occlusions. Asdescribed in that patent, the infusion of arterial blood into the venoussinuses provides a retrograde venous flow that traverses the capillarybed to oxygenate the ischemic tissues and at least partially resolveischemic brain symptoms.

One drawback associated with the technique described in the Frazeepatent is that the pressure in the transverse venous sinuses must becontinuously monitored to ensure that cerebral edema is avoided. Becausethe veins are much less resilient than arteries, the application ofsustained pressure on the venous side may cause brain swelling, whiletoo little pressure may result in insufficient blood delivered to thearterial side.

In addition to the foregoing methods to augment cerebral perfusion,several methods are known for mechanically removing clots to treatcerebral occlusions. U.S. Pat. No. 5,895,398 to Wensel et al. describesa shape-memory coil affixed to an insertion mandrel. The coil iscontracted to a reduced profile state within the lumen of a deliverycatheter, and the catheter is used to cross a clot. Once the coil isdisposed distal to the clot, the coil id deployed. The coil then isretracted proximally to engage and remove the clot.

A primary drawback associated with the Wensel device is that thedeployed coil contacts the intima of the vessel, and may damage to thevessel wall when the coil is retracted to snare the occlusion.Additionally, the configuration of the coil is such that the device maynot be easily retrieved once it has been deployed. For example, once thecatheter has been withdrawn and the coil deployed distal to theocclusion, it will be difficult or impossible to exchange the coil foranother of different dimensions.

U.S. Pat. No. 5,972,019 to Engelson et al. describes a deployable cageassembly that may be deployed distal to a clot. Like the Wensel device,the Engelson device is depicted as contacting the intima of the vessel,and presents the same risks as the Wensel device. In addition, becausethe distal end of the device comprises a relatively large profile, therisk of dislodging emboli while crossing the clot is enhanced, andmaneuverability of the distal end of the device through tortuousvasculature may be reduced.

In view of these drawbacks of previously known clot removal apparatusand methods, it would be desirable to provide apparatus and methods forcontrolling hemodynamic properties at selected locations in the cerebralvasculature, e.g., the Circle of Willis and communicating vessels.

It also would be desirable to provide apparatus and methods for removaland recovery of thrombi and/or emboli above the carotid bifurcation.

It still further would be desirable to provide apparatus and methodsthat quickly and efficiently treat cerebral occlusions.

It still further would be desirable to provide apparatus and methods forselectively providing retrograde and/or antegrade flow to desiredregions in the cerebral vasculature to effectively remove emboli.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention toprovide apparatus and methods for controlling hemodynamic properties atselected locations in the cerebral vasculature.

It is also an object of the present invention to provide apparatus andmethods for removal and recovery of thrombi and/or emboli above thecarotid bifurcation.

It is a further object of the present invention to provide apparatus andmethods that quickly and efficiently treat cerebral occlusions.

It still a further object of the present invention to provide apparatusand methods for selectively providing retrograde and/or antegrade flowto desired regions in the cerebral vasculature to effectively removeemboli.

These and other objects of the present invention are accomplished byproviding a stroke treatment system comprising an emboli removalcatheter and one or more flow control devices suitable for manipulatingblood flow in the cerebral vasculature. The stroke treatment system mayfacilitate the introduction and subsequent removal of clot lysingagents, or further comprise a thrombectomy element.

In a preferred embodiment, the emboli removal catheter is transluminallyinserted and disposed in the common carotid artery CCA, and comprises aflexible catheter having an occlusive member disposed on its distal end.The occlusive member is configured to be deployed to anchor the catheterand occlude antegrade flow in the CCA. A separate occlusive element isconfigured to pass through a lumen of the emboli removal catheter, andis deployed in the external carotid artery ECA to occlude flow throughthat vessel.

One or more flow control devices, each having a rapidly deployableocclusive member, then are positioned at selected locations, e.g., inthe subclavian arteries, and may be deployed to isolate or redistributeflow through the cerebral vasculature. Preferably, the flow controldevices occlude blood flow in the vertebral and carotid arteries in thehemisphere in which the occlusion is not located. This temporarilyinfluences flow in the opposing hemisphere. Preferably, the flow controldevices are provided in sufficient number that, when deployed, the flowcontrol devices substantially influence the flow dynamic of mid-cerebralartery.

Once the foregoing components have been deployed, a lysing agent may beintroduced into the vessel through a lumen of the emboli removalcatheter. After an appropriate period, the occlusive members on one ormore of the flow control devices may be collapsed to cause retrogradeflow through the cerebral vasculature sufficient to flush the lysingagent and any emboli or debris from the vasculature into the emboliremoval catheter. The stroke treatment system and flow control devicesmay then be withdrawn from the patient's vasculature.

Alternatively, a thrombectomy element may be advanced transluminally viathe ICA to a position just proximal of a cerebral occlusion, e.g., inthe middle cerebral artery, after placement (but prior to deployment) ofthe flow control devices. The flow control devices then are deployed toselectively and temporarily redistribute or suspend flow in the cerebralvasculature. The thrombectomy element preferably is advanced to the siteof the cerebral occlusion through a lumen of the emboli removalcatheter.

With flow controlled throughout the Circle of Willis and therefore thecommunicating mid-cerebral artery, the thrombectomy element then isengaged with the lesion. Actuation of the thrombectomy elementpreferably causes mechanical disruption of the emboli or thrombus, afterwhich the element is retracted into the emboli removal catheter. Byselectively de-actuating one or more of the flow control devices,retrograde or redistributed flow may be generated in the vasculaturethat cases emboli liberated during actuation of the thrombectomy elementto be directed into the emboli removal catheter. The flow controldevices then are withdrawn to reestablish antegrade blood flow.

In a further alternative embodiment, a second emboli removal cathetermay be disposed in a vertebral artery in lieu of one of the flow controldevices. In this embodiment, the lumen of the second emboli removalcatheter may be perfused with blood or saline under pressure to induceretrograde flow elsewhere in the cerebral vasculature, such as in thecarotid or vertebral arteries. Additionally, chilled blood and/or drugagents may be delivered via the second catheter to induce mildhypothermia and/or altered pressure gradients at selected cerebrallocations.

The second emboli removal catheter may be used to enhance flowmanipulation in the Circle of Willis and communicating vessels tofacilitate removal of emboli via either retrograde or antegrade floweither independently or, or simultaneously with, use of the first emboliremoval catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawings and the followingdetailed description of the preferred embodiments, in which:

FIG. 1 provides a schematic overview of the portion of the vasculaturein which the apparatus and methods of the present invention are intendedfor use;

FIG. 2 provides an overview of the apparatus of the present inventiondeployed in a patient's vasculature;

FIGS. 3A-3D are, respectively, a schematic view, and detailed side andsectional views of the distal end of an emboli removal catheter of thepresent invention;

FIGS. 4A-4E provide detailed views of the proximal and alternativedistal ends of the flow control devices of the present inventioncontracted and expanded states;

FIGS. 5A-5B are views of alternative embodiments of low profileocclusive elements for occluding flow in the external carotid arteries;

FIGS. 6A-6F depict thrombectomy wires having shape memory properties incontracted and deployed states;

FIGS. 7A-7E illustrate alternative configurations for the thrombectomywire of FIG. 6;

FIGS. 8A-8D illustrate thrombectomy wires configured to engage thefibrin strands of a thrombus;

FIGS. 9A-9C describe an alternative thrombectomy device configured toengage the fibrin strands of a thrombus;

FIGS. 10A-10E illustrate method steps for removing an occlusion usingthe apparatus of FIG. 9;

FIG. 11 describes a telescoping catheter configured to be advancedthrough the main catheter;

FIGS. 12A-12D describe a telescoping catheter having an expandabledistal section configured to be advanced through the main catheter;

FIGS. 13A-13H illustrate method steps for controlling cerebral bloodflow and removing thrombi and/or emboli in accordance with the presentinvention;

FIGS. 14A-14B describe a catheter having an intake port configured toprovide for retrograde and/or antegrade flow in either of the carotid orvertebral arteries;

FIG. 15 illustrates a proximal assembly suitable for controllingretrograde and antegrade flow in the carotid and vertebral catheters ofFIG. 14; and

FIGS. 16A-16B provide examples of manipulating cerebral flow using acombination of carotid and vertebral catheters, each having antegradeand retrograde flow potential.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a schematic of the pertinent vasculature relatingto the present invention is provided. Many cerebral obstructions thatlead to stroke reside in the middle cerebral arteries MCA. To treatobstructions in the MCA, one approach involves percutaneously andtransluminally advancing a therapeutic device to the site of theobstruction via the internal carotid artery ICA.

It is well known in the art to percutaneously and transluminally advancea catheter in retrograde fashion toward coronary vasculature, e.g., viathe femoral artery, external iliac artery, descending aorta DA andaortic arch AA. To access cerebral vasculature, including obstructionsresiding in the MCA, one approach is to further advance a catheterand/or therapeutic devices in antegrade fashion from the aortic arch AA,into the common carotid artery CCA, up through the ICA and into themiddle cerebral artery MCA, as shown in FIG. 1.

Treating occlusions in the MCA may generate emboli upon removal of theocclusion. Under normal blood flow conditions, such emboli may traveldownstream from the original occlusion and cause ischemia. Accordingly,it is advantageous to manipulate blood flow characteristics in thecerebral vasculature to ensure that emboli generated in the MCA areeffectively removed.

The present invention manipulates cerebral blood flow by inhibiting flowfrom the heart into any of the vertebral arteries VA and common carotidarteries CCA. This may be achieved by disposing flow control devices inthe subclavian arteries SA and/or brachiocephalic trunk BT, totemporarily inhibit flow from the aortic arch AA into any of thevertebral arteries VA and common carotid arteries CCA. This interruptionof antegrade flow may advantageously alter flow in the Circle of Willis,as described hereinbelow.

FIG. 2 provides an overview of the components of the system of thepresent invention, each of which are described in greater detailhereinbelow.

Flow control devices 8 having occlusive elements 6 are configured to beintroduced into the patient's vasculature, e.g., via the radial orbrachial arteries. When so positioned, occlusive elements 6 preferablyare positioned in the patient's left subclavian artery SA andbrachiocephalic trunk BT, as shown. Occlusive elements 6 may have any ofa number of designs, with low profile mechanically self-expandingdesigns being preferred.

Emboli removal catheter 2 includes distal occlusive element 4, and isconfigured to be percutaneously advanced in retrograde fashion throughthe descending aorta. Occlusive element 4 preferably comprises apear-shaped or funnel-shaped balloon as described in copending andcommonly assigned U.S. patent application Ser. No. 09/418,727, which isincorporated herein by reference. Occlusive element 4 preferably ispositioned proximal to the carotid bifurcation, and then deployed toinduce retrograde flow in the ICA by use of a venous return catheter(not shown) that communicates with the proximal end of catheter 2.Balloon 10, also described in the foregoing application, is deployed inthe ECA to ensure that retrograde flow from the ICA is not carried in anantegrade fashion into the ECA.

Flow control devices 8 and emboli removal catheter 2 are used to suspendantegrade flow in the cerebral arteries and to selectively suspend orredistribute flow in the cerebral vasculature. Once so-deployed, alysing agent may be introduced to dissolve the clot, followed byselectively contracting one or more of the flow control devices toinduce retrograde flow through emboli removal catheter 2.

Alternatively, after placement of flow control devices 8, but beforethey are deployed, thrombectomy wire 12 may be introduced into thevessel containing the lesion. Flow control devices 8 then may bedeployed, as shown in FIG. 2, to prevent flow from the aortic arch AAinto the right common carotid artery RCCA and the right and leftvertebral arteries VA. Such selective manipulation of flow into thecarotid and/or vertebral arteries alters flow characteristics in thecerebral vasculature, and permits retrograde flow through to be inducedto flush emboli and debris into the lumen of catheter 2 for removal.

In the embodiment of FIG. 2, thrombectomy wire 12 comprises knot 14 thatis deployed distal to the thrombus T. Thrombectomy wire 12 and thrombusT then are retracted proximally into the lumen of emboli removalcatheter 2, and any embolic fragments generated during this procedureare directed into catheter 2 by inducing localized retrograde flow. Oncethe thrombus is removed, flow control devices 8 are contracted toreestablish flow to the cerebral vasculature.

Referring now to FIG. 3A, stroke treatment apparatus 40 constructed inaccordance with the principles of the present invention is described.Apparatus 40 comprises emboli removal catheter 41, wire 45, venousreturn line 52, tubing 49 and optional blood filter 50.

Catheter 41 includes distal occlusive element 42, hemostatic ports 43 aand 43 b, e.g., Touhy-Borst connectors, inflation port 44, and bloodoutlet port 48. Wire 45 includes balloon 46 that is inflated viainflation port 47. Tubing 49 couples blood outlet port 48 to filter 50and blood inlet port 51 of venous return line 52.

Wire 45 preferably comprises a small diameter flexible shaft having aninflation lumen that couples inflatable balloon 46 to inflation port 47.Wire 45 and balloon 46 are configured to pass through hemostatic ports43 a and 43 b and the aspiration lumen of catheter 41 (see FIGS. 3C and3D), so that balloon 46 may be disposed in a communicating artery, e.g.,the external carotid artery. Ports 43 a and 43 b and the aspirationlumen of catheter 41 are sized to permit additional interventionaldevices, such as thrombectomy wires, to be advanced through theaspiration lumen when wire 45 is deployed.

Venous return line 52 includes hemostatic port 53, blood inlet port 51and a lumen that communicates with ports 53 and 51 and tip 54. Venousreturn line 52 may be constructed in a manner per se known for venousintroducer catheters. Tubing 49 may comprise a suitable length of abiocompatible material, such as silicone. Alternatively, tubing 49 maybe omitted and blood outlet port 48 of catheter 41 and blood inlet port51 of venous return line 52 may be lengthened to engage either end offilter 50 or each other.

With respect to FIGS. 3B and 3C, distal occlusive element 42 comprisesexpandable funnel-shaped balloon 55. In accordance with manufacturingtechniques which are known in the art, balloon 55 comprises a compliantmaterial, such as polyurethane, latex or polyisoprene which has variablethickness along its length to provide a funnel shape when inflated.Balloon 55 is affixed to distal end 56 of catheter 41 in an invertedfashion, for example, by gluing or a melt-bond, so that opening 57 inballoon 55 leads into aspiration lumen 58 of catheter 41. Balloon 55preferably is wrapped and heat treated during manufacture so that distalportion 59 of the balloon extends beyond the distal end of catheter 41and provides an atraumatic tip or bumper for the catheter.

As shown in FIG. 3D, catheter 41 preferably comprises inner layer 60 oflow-friction material, such as polytetrafluoroethylene (“PTFE”), coveredwith a layer of flat stainless steel wire braid 61 and polymer cover 62(e.g., polyurethane, polyethylene, or PEBAX). Inflation lumen 63 isdisposed within polymer cover 62 and couples inflation port 44 toballoon 55.

Referring to FIG. 4, features of the flow control devices of the presentinvention are described. The flow control devices may comprise either aninflatable balloon or a mechanically deployable mechanism. In FIG. 4A, apreferred embodiment of the proximal end for a mechanically deployablemechanism comprises controller 70, delivery port 78, e.g., fordelivering cardioplegic agents, deployment knob 72 that is configured toslide within slot 74, and guidewire lumen 76, which may comprise aself-sealing valve. Body 73 houses a plurality of lumens, e.g., amechanical deployment lumen, a therapeutic drug delivery lumen, and aguidewire lumen. In an alternative embodiment, for use in conjunctionwith an inflatable balloon, port 78 may serve as an inflation/aspirationport while deployment knob 72 and slot 74 are omitted.

FIGS. 4B-4C illustrate the distal end of the flow control device havinginflatable balloon 82 in contracted and deployed states, respectively.In use, body 73 is advanced over a guidewire via guidewire lumen 86.Radiopaque tip marker 84 may be used to aid in fluoroscopically guidingthe device. Balloon 82 then is inflated by a lumen within body 73 thatcommunicates with port 78. Port 78 may communicate with a timingmechanism (not shown) that automatically deflates balloon 82 after apredetermined time, e.g., 15 seconds, to ensure that cerebral blood flowis not inhibited for a period so long as to cause cerebral compromise.

FIGS. 4D-4E illustrate mechanically deployable mechanism 92 comprisingflexible wires 95 and impermeable coating 97 in contracted and deployedstates, respectively. Impermeable coating 97 comprises an elastomericpolymer, e.g., latex, polyurethane or polyisoprene. The proximal end ofdeployable mechanism 92 is affixed to body 73. The distal end ofmechanism 92 is affixed to distalmost section 99, which in turncommunicates with sliding member 93 that is configured to slidelongitudinally within a lumen of body 73.

Upon actuating deployment knob 72, i.e., proximally retracting knob 72within slot 74, sliding member 93 and distalmost section 99 areproximally retracted relative to body 73, to compress flexible wires 95.Impermeable coating 97 conforms to the shape of wires 95 to provide aplug-shaped occlusive member, as shown in FIG. 4E. Deployment knob 72may communicate with a timing mechanism (not shown) that automaticallyreleases mechanism 92 after a predetermined time.

Referring to FIG. 5, alternative embodiments for guide wire 45 andballoon 46 of FIG. 3A are described for use in occluding a communicatingartery, e.g., the external carotid artery. In FIG. 5A, occlusive device121 comprises proximal hub 120, hypo tube 127, shaft 128, balloon 136and coil 142. Hypo tube 127 preferably comprises stainless steel, whileshaft 128 preferably comprises a radiopaque material. Balloon 136 isconfigured using a tubular balloon material, e.g., chronoprene, that iscompliant in nature and provides a self-centering balloon when deployed.The proximal end of balloon 136 is secured to radiopaque shaft 128 byband 132 and taper 130. The distal end of balloon 136 is affixed to coil142 via taper 140.

Core wire 122 is slidably disposed within hypo tube 127 so that itsproximal end and is disposed in proximal hub 120 and its distal end isaffixed to taper 140. Fluid may be injected into the annulus surroundingcore wire 122 so that the fluid exits into balloon 136 via inflationwindow 134, thus permitting balloon 136 to expand radially andlongitudinally. Core wire 122, taper 140 and coil 142 may move distallyto accommodate such linear extension. Stroke limiter 123, disposed onthe distal end of core wire 122, ensures that balloon 136 does notextend longitudinally more a predetermined distance ‘x’.

In the alternative embodiment of FIG. 5B, occlusive device 151 comprisesshaft 152, balloon 158, and coil 168. Shaft 152 preferably comprises aradiopaque material and connects to a hypo tube similar to that of FIG.5A. The proximal components for device 151, i.e., proximal to shaft 152,are the same as the components that are proximal to shaft 128 in FIG.5A.

Balloon 158 is constrained at its proximal end by band 156 havingproximal balloon marker 157. Taper 154 is provided on the proximal endof band 156 in alignment with the proximal end of balloon 158. Thedistal end of balloon 158 is everted, as shown in FIG. 5B, and securedwith radiopaque band 160 that provides a fluoroscopic reference for thedistal boundary of the balloon. Taper 164 further secures the everteddistal section, sandwiching between the first and second folds.

Core wire 150 is distally affixed to coil 168 having radiopaque marker170. Lumen 159 communicates with an inflation port (not shown) at itsproximal end and with inflation window 136 at its distal end. Lumen 159permits the injection of fluids, e.g., saline, to deploy balloon 158.Core wire 150 is slidably disposed in the hypo tube and shaft 152 toprevent extension of balloon 158 up to a distance ‘x’, as indicated inFIG. 5A.

Referring to FIG. 6, apparatus suitable for removing thrombi aredescribed. In FIG. 6A, thrombectomy wire 200 having ball 202 affixed toits distal end is depicted in a contracted state within coil 204. In apreferred embodiment, thrombectomy wire 200 comprises a shape-memoryretaining material, for example, a Nickel Titanium alloy (commonly knownin the art as Nitinol).

The use of Nitinol generally requires the setting of a custom shape in apiece of Nitinol, e.g., by constraining the Nitinol element on a mandrelor fixture in the desired shape, and then applying an appropriate heattreatments, which are per se known.

Coil 204 covers wire 202 along its length, up to ball 202. As coil 204is retracted proximally, wire 200 self-expands to a predetermined knotconfiguration, as shown in FIG. 6B. In a preferred embodiment, thediameter of wire 200 is about 0.002 inches, the diameter of ball 202 isabout 0.014 inches, and coil 204 is manufactured using platinum. Itshould be appreciated that an outer sheath may be used in place of coil204, such that proximally retracting the outer sheath causes wire 200 todeploy.

Referring to FIG. 6C, a method for using thrombectomy wire 200 to snarea thrombus T, e.g., in middle cerebral artery MCA, is described.Thrombectomy wire 200, initially contracted within coil 204, is advancedthrough a lumen of catheter 2, then preferably is advanced in retrogradefashion via the internal carotid to the site of the cerebral lesion inthe MCA. Under controlled flow conditions, i.e., conditions that willpromote the flow of emboli toward catheter 2, wire 200 and coil 204pierce thrombus T, as shown in FIG. 6C.

Coil 204 then is retracted proximally with respect to wire 200 toself-deploy shape memory wire 200 at a location distal to thrombus T, asshown in FIG. 6D. Wire 200 then is retracted to snare thrombus T, andball 202 of wire 200 facilitates removal of the lesion.

Referring to FIGS. 6E-6F, an alternative embodiment a thrombectomy wireof FIGS. 6A-B is described. In FIG. 6E, thrombectomy wire 205 havingdistal ball 208 is delivered in a contracted state within slidablesheath 206. Thrombectomy wire 205 is configured to self-deploy to apredetermined shape, e.g., via use of a shape memory material, uponproximal retraction of sheath 206. Coil 207 overlays slidable sheath 206and is affixed to ball 208 at points 209 a and 209 b, e.g., via a solderor weld. Sheath 206 is initially provided in a distalmost position suchthat it abuts ball 208 and constrains wire 205 along its length. Sheath206 advantageously enhances the distal pushability of the device,particularly when the device is advanced though an occlusion.

Upon positioning the distal end of wire 205 at a location distal to theocclusion, sheath 206 is retracted proximally to cause wire 205 toself-deploy to a knot-shaped configuration, as depicted in FIG. 6F. Coil207, affixed to ball 208 of wire 205, conforms to the shape of wire 205.The deployed knot-shaped device then is proximally retracted to snarethe occlusion, according to methods described hereinabove.

Referring to FIGS. 7A-7E, alternative embodiments for thrombectomy wiresin accordance with the present invention are depicted. In FIG. 7A,thrombectomy wire 210 comprises a plurality of intersecting hoops thatdeploy upon retraction of a coil or sheath. Hoops 212 and 214 may beorthogonal to each other, as shown in FIG. 7A. The hoops are designed toform a knot-shape to snare a thrombus in combination with ball 216.Additionally, there may be a series of intersecting hoops, as shown inFIG. 7B. Thrombectomy wire 220 comprises first knot 222 and second knot224 separated by a distance ‘y’, although it will be obvious that anyvariation in the number of knots and their shapes are intended to fallwithin the scope of the present invention.

Referring to FIG. 7C, thrombectomy wire 230 comprises spiral-shapeddistal section 232. The spiral shape is formed from a series of planarhoops, the diameter of hoops being slightly smaller with each successivehoop. As shown, the hoops of spiral 232 are depicted as being orthogonalto the main axis of wire 230. Elbow 234 defines a bent section thatconnects main wire section 236 to first hoop 238. As shown, elbow 234 isorthogonal to main wire section 236, however, it may be provided at anyangle. Similarly, as shown in FIG. 7D, wire 240 may comprise a pluralityof spiral-shaped sections 242 and 244 separated by a distance ‘z’.

In FIG. 7E, thrombectomy wire 250 comprise a plurality of petal-shapedsections that deploy upon retraction of a coil or sheath. As shown,petal-shaped sections 252 and 254 are orthogonal to each other, however,they may be provided at any angle with respect to main axis 256 and eachother, and any number of petal-shaped sections may be provided

Referring to FIGS. 8A-8D, a further alternative thrombectomy device isillustrated. Device 260 removes a lesion by organizing the fibrinstrands of the lesion around the deployable wires using a rotationalmotion. Exemplary method steps for using the embodiments described inFIGS. 8A-8D are described in FIG. 10 hereinbelow.

In FIG. 8A, thrombectomy device 260 comprises at least one deployablewire 262 affixed at its proximal and distal ends at points 266 and 264,respectively. Deployable wire 262 is initially contracted within coil268, and when tubular member 268, e.g., a coil or sheath, is retractedproximally, deployable wires 262 self-expand to a predetermined shape,as shown. As deployable wires 262 are rotated within the thrombusitself, the fibrin strands of the thrombus will become engaged with andwrap around deployable wires 262.

In FIG. 8B, alternative thrombectomy device 270 comprises at least onedeployable wire 274 that is distally affixed to wire 270 at point 276.The proximal end of wire 274 is secured to sliding member 272, whichslides longitudinally over wire 271. When wire 271 and sliding member272 move with respect to each other, deployable wire 274 either radiallyoutwardly deflects, as shown, or flattens out for a contracted position.

In FIG. 8C, thrombectomy device 280 comprises deployable wire 282configured to form a plurality of loops 285 around shaft 283. The distalend of deployable wire 282 is affixed to shaft 283 at point 284, whichmay serve as an atraumatic tip for guiding the device and piercing thethrombus. The proximal end of deployable wire 282 is affixed to tube281. Tube 281 spans-the length of the device and has a proximal end thatis manipulated by the physician. Distally advancing tube 281 over shaft283 deploys loops 285, as shown, while proximally retracting tube 281with respect to shaft 283 contracts loops 285. In the deployed state,rotating the device about its axis will cause loops 285 of wire 282 toengage the thrombus and wrap the fibrin strands about the device, asdescribed in FIG. 10 hereinbelow.

In FIG. 8D, thrombectomy device 290 comprises a plurality ofshape-memory, arrowhead-shaped wires 292 that are distally affixed toeach other at point 294 and proximally affixed at junction 298. Wires292 are initially contracted within tubular member 296, e.g., a coil orsheath, and upon proximal retraction of tubular member 296, wires 292self-deploy to the configuration shown.

Apparatus and methods for organizing fibrin strands of a thrombus arounda thrombectomy device are further described with respect to FIGS. 9 and10. In FIG. 9A, thrombectomy device 300 comprises proximal segment 306,catheter 302, and distal segment 304. Proximal segment 306 comprisesthumb ring 308, proximal body 310, and deployment knob 312 that slideslongitudinally within slot 314. Distal segment 304 comprises at leastone deployable wire 316 and atraumatic tip 318.

FIG. 9B provides a schematic view of distal segment 304. Deployable wire316 preferably comprises a shape memory material that communicates withdeployment knob 312 at its proximal end, as described in FIG. 9Chereinbelow. The distal end of deployable wire 316 is affixed toatraumatic tip 318, e.g., using a solder or weld. Deployable wire 316 isdelivered in a contracted state, i.e., such that it does notsubstantially extend radially beyond catheter 302. Upon actuation ofdeployment knob 312, wire 316 self-expands via holes 317 to form awhisk-type element, as shown. Catheter 302 may be provided with one ormore working lumens that communicate with delivery port 305 to permitthe delivery of fluids, e.g., saline or other drugs that facilitate clotremoval.

FIG. 9C provides a schematic view of proximal segment 306. The distalend of deployable wire 316 is configured to deploy from catheter 302.The proximal end of catheter 302 is affixed to outer shaft 322, whichpreferably has a square cross-section. Outer shaft 322 is keyed to innershaft 320. Inner shaft 320 is keyed to slidably more actuator 323, sothat rotational motion of one element causes rotation of the other.Catheter 302 further is affixed to retainer 315, which permits catheter302 to rotate freely relative to proximal body 310.

Thumb ring 308 communicates with actuator 323 via joint 321. Joint 321permits rotational motion of actuator 323 with respect to thumb ring308. Actuator 323 is affixed to rotational member 326 at its distal end,which in turn is affixed to inner shaft 320. Rotational member 326comprises knob 327 that is configured to slidably rotate within groove328 in the wall of body 310.

Deployable wire 316 is deployed by sliding deployment knob 312 withinslot 314. Deployment knob 312 comprises a rounded pin that engages witha groove of ring 324. This engagement distally advances ring 324 withinslot 325 of catheter 302. Deployable wire 316 is affixed to ring 324,such that distally advancing ring 324 via deployment knob 312 allowswire 316 to self-deploy. The rounded pin engagement between knob. 312and the groove of ring 324 further permits free axial rotation of ring324 while knob 312 is stationary.

With wire 316 deployed, thumb ring 308 is depressed with a force thatovercomes a resistance force provided by spring 330. Depressing thumbring 308 in turn causes rotational member 326 to be advanced distallyvia groove 328. When a thumb force is no longer applied, the resistanceof spring 330 then pushes rotating member 326 in a proximal directionvia groove 328. This in turn causes rotation of rotational member 326,inner shaft 320, outer shaft 322 and catheter 302. The rotation ofcatheter 302 generates rotation of thrombectomy wire 316.

The rotation of thrombectomy wire 316 may be clockwise,counterclockwise, or a combination thereof by manipulating the profileof groove 328. The rotational speed may be controlled by varying theresistance of spring 330, and the duration of rotation can be controlledby varying the length in which rotational member 326 can longitudinallymove. Alternatively, another force transmission means, e.g., a motor,may be coupled to the proximal end to provide for controlled axialrotation of catheter 302.

FIG. 10 illustrate method steps for removing thrombi using any of thethrombectomy devices described in FIGS. 8-9. In a first step, catheter302 is advanced through catheter 2 of FIG. 2, then advanced in aretrograde fashion toward the occlusion. Catheter 302 may be advancedvia the internal carotid artery to treat a lesion T located in acerebral vessel V, e.g., the middle cerebral artery. Atraumatic tip 318serves to protect vessel walls as catheter 302 is advanced throughtortuous anatomy. At this time, flow control devices 8 of FIG. 2 aredeployed to cause retrograde blood to flow in the directions indicated.

Tip 318 of catheter 302 then is advanced to pierce thrombus T, as shownin FIG. 10B. Deployment knob 312 of FIG. 9 then is actuated to deploy atleast one deployable wire 316 within thrombus T. Thumb ring 308 then isdepressed, resulting in the controlled rotation of deployable wire 316,such that the wire engages the fibrin strands of thrombus T. As thefibrin strands are wound about deployable wire 316, the diameter ofthrombus T decreases, as shown in FIG. 10D. Blood flows in a retrogradefashion, i.e., toward catheter 2 which is positioned in the commoncarotid artery, and any emboli E generated during the procedure will beremoved by the catheter in the process. It should be noted thatdeployable wire 316 is designed such that it does not contact the innerwall of vessel V. Once the thrombus T is sufficiently wound aboutdeployable wire 316, as shown in FIG. 10E, catheter 302 may be retractedinto catheter 2.

Referring to FIG. 11, an alternative embodiment of the present inventionis described wherein a second catheter is advanced to a location incloser proximity to the occlusive lesion. Main catheter 340 havingdistal occlusive element 342 is positioned, for example, in the commoncarotid artery, as described in FIG. 2. Recovery catheter 344 havingdistal occlusive element 346 and radiopaque marker 347 is configured totelescope within the lumen of main catheter 340.

In a preferred method, main catheter 340 is disposed in the commoncarotid artery. Retrograde flow then is established using venous returnline 52 of FIG. 3A according to methods described hereinabove. A 0.014inch neuro guidewire 350 then is advanced via the lumen of main catheter340 to the site of the cerebral occlusion, and neuro guidewire 350 isdisposed distal to the lesion. In this illustration, an occlusion (notshown) would be located approximately within an interval ‘L’, e.g., inthe middle cerebral artery. Recovery catheter 344 then is advanceddistally over neuro guidewire 350 and is positioned proximal toocclusion ‘L’. Upon positioning recovery catheter 344, occlusive distalelement 346 is deployed.

Neuro catheter 348 then is advanced over neuro guidewire 350, and thedistal end of neuro catheter 348 is disposed at a location distal toocclusion ‘L’, as shown. Neuro guidewire 350 then is retractedproximally and removed from within neuro catheter 348, which comprises arelatively small lumen. With neuro guidewire 350 removed, a thrombectomywire is advanced distally through the lumen of neuro catheter 348, andthe thrombectomy wire takes the place of guidewire 350 in FIG. 11. Neurocatheter 348 then is proximally retracted, and thrombectomy wire 350 isdeployed to treat the occlusion according to methods describedhereinabove.

Recovery catheter 344 comprises at least one blood venting hole 345. Theestablished retrograde flow through catheter 344 using venous returnline 52 induces retrograde flow in at least the internal carotid arteryvia blood venting hole 345. Flow into venting hole 345 may bemanipulated by actuating inner sheath 349, e.g., by longitudinallysliding inner sheath 349 within catheter 344, or rotating inner sheath349 relative to its longitudinal axis.

Advantageously, the distal end of recovery catheter 344 is positioned inclose proximity to the lesion, so that wire 348 and any emboli generatedare immediately confined within recovery catheter 344. Furthermore,advancing recovery catheter 344 via the internal carotid arteryeliminates the need for deploying balloon 10 of FIG. 2 in the externalcarotid artery.

Referring to FIG. 12, a further alternative embodiment of the presentinvention is described wherein a second catheter is advanced to alocation in closer proximity to the occlusive lesion. Main catheter 360having distal occlusive element 362 is positioned, for example, in thecommon carotid artery, as described in FIG. 2. Recovery catheter 364comprises a wire weave configuration and may be manufactured using ashape memory material, e.g., Nitinol, as described hereinabove.

Recovery catheter 364 further comprises blood impermeable membrane 365,such as latex, polyurethane or polyisoprene, that encloses the wireweave of recovery catheter 364. The elastic properties of bloodimpermeable membrane 365 allow it to conform to the contracted andexpanded states of recovery catheter 364.

Recovery catheter 364 is advanced in a contracted state within outersheath 366. As described in applicants' commonly assigned, co-pendingapplication Ser. No. 09/916,349, which is herein incorporated byreference, outer sheath 366 is retracted proximally to cause occlusivedistal section 368 to self-expand to a predetermined deployedconfiguration, as shown in FIG. 12A. Occlusive distal section 368 may besized for different vessels, e.g., the middle cerebral arteries, so thatthe distal end of recovery catheter 364 is disposed proximal to anocclusion, e.g., as depicted at location ‘L’. Mouth 369 provides arelatively large distal opening, i.e., flush with the inner wall of thetargeted vessel.

Neuro catheter 370 then is advanced over neuro guidewire 372, asdescribed hereinabove in FIG. 11, and a thrombectomy wire is exchangedfor neuro guidewire 372. Neuro catheter 370 is proximally retracted, andthrombectomy wire 372 removes the occlusion at location ‘L’ according tomethods described hereinabove. Upon removing the occlusion, thrombectomywire 372 is retracted into mouth 369, along with any emboli generatedduring the procedure.

It will be advantageous to collapse mouth 369 upon completion of theprocedure, to prevent thrombi and/or emboli from exiting removalcatheter 364. FIGS. 12B-12D illustrate a method for effectivelycollapsing mouth 369 proximally to distally, as shown. FIG. 12B showsouter sheath 366 having radiopaque marker 367 in a proximally retractedposition that allows occlusive distal section 368 to deploy. Afterdirecting thrombi and/or emboli into mouth 369, outer sheath 366 isadvanced distally to collapse mouth 369, as shown sequentially in FIGS.12C-12D. This effectively confines thrombi and/or emboli within mouth369.

Referring now to FIG. 13, a method for using the apparatus describedhereinabove to treat stroke, in accordance with principles of thepresent invention, is described. In FIG. 13A, flow control devices 400having controllers 402 are introduced into the patient's vasculature ina contracted state, e.g., via the radial or brachial arteries, andpreferably are positioned in the patient's left subclavian artery andbrachiocephalic trunk, as shown. It will be appreciated by those skilledin the art that varying the number of flow control devices and theirplacements is intended to fall within the scope of the presentinvention. Blood flow occurs in the directions indicated.

Referring to FIG. 13B, catheter 404 of FIG. 3A is positioned in thecommon carotid artery CCA using guide wire 406. Catheter 404 ispositioned proximal to the carotid bifurcation, as shown, preferably inthe hemisphere in which the cerebral occlusion is located. Balloon 408,for example, as described in FIG. 5, then is disposed in the externalcarotid artery and deployed, as shown in FIG. 13C.

Referring to FIG. 13D, distal occlusive element 412 of catheter 404 isdeployed to occlude antegrade flow in the selected CCA. Venous returncatheter 52 of FIG. 3A then is placed in a remote vein, such thatnegative pressure in venous return catheter 52 during diastoleestablishes a continuous flow through the lumen of catheter 404. Thisinduces retrograde flow in the ICA, as depicted in FIG. 13D. Athrombectomy wire 414, for example, as described in FIGS. 6-10, isadvanced through catheter 404 and into the cerebral vasculature via theICA.

Referring to FIG. 13E, a view of the cerebral vasculature under theconditions described in FIG. 13D is shown. Thrombectomy wire 414 hasbeen advanced to a location just proximal to thrombus T, for example, inmiddle cerebral artery MCA.

At this time, flow control devices 400 then are deployed usingcontroller 402 to form occlusive elements 420, as shown in FIG. 13F. Asdepicted, flow from aortic arch AA into brachiocephalic trunk BT andleft subclavian artery SA are inhibited, which in turn inhibits flowinto the vertebral arteries VA and right CCA, as shown. It will beapparent to those skilled in the art that occlusive elements 420 may beselectively placed at other locations to permit and/or inhibit flow intothe selected locations of the cerebral vasculature.

The deployment of occlusive elements 420 controls flow in the Circle ofWillis, as shown in FIG. 13G. In this example, since arterial flow intothe vertebral arteries VA and the right internal carotid artery has beeninhibited, emboli that are generated will be directed in a retrogradefashion toward catheter 404 via the left internal carotid artery. Thedistal end of thrombectomy wire 414 then pierces thrombus T anddeployable knot 416 is deployed distal to the thrombus, as shown in FIG.13G. Alternatively, other thrombectomy wire configurations may be usedto treat the lesion, as described in FIGS. 6-10.

Deployable knot 416 of thrombectomy wire 414 snares thrombus T, as shownin FIG. 13H, and subsequently is retracted into catheter 404. Any emboligenerated during the procedure will be directed into catheter 404 viathe established retrograde flow. Occlusive elements 420, distalocclusive element 412, and external carotid occlusive device 408 thenare contracted, and catheter 404 may be removed from the patient.

It should be noted that the method steps described in FIG. 13 may beused in combination with any of the apparatus described hereinabove. Forexample, recovery catheters 344 and 364 of FIGS. 11 and 12,respectively, may be advanced through catheter 404 of FIG. 13.Additionally, any of the snaring thrombectomy devices of FIG. 7 or therotating thrombectomy devices of FIG. 8 may be used in place ofthrombectomy wire 414 as depicted. Similarly, any of the occlusivedevices described in FIGS. 4B-4E and FIGS. 5A-5B may be used in place ofocclusive elements 420 and 408, respectively.

Referring to FIGS. 14-16, further apparatus and methods is accordancewith principles of the present are described. In FIG. 14A, catheter 430may be configured for use in any of the carotid and vertebral arteries.Catheter 430 comprises blood intake port 432, distal occlusive element436 and radiopaque tip marker 435. Occlusive element 436 comprisesproximal and distal tapers 438 and 440, respectively. Inner sheath 434is configured for longitudinal sliding motion within catheter 430.

Inner sheath 434 is initially provided in a distalmost position thatcovers blood intake port 432 in a closed state, as shown in FIG. 14A.Deployment of occlusive element 436 inhibits antegrade blood flow invessel V, at which time therapeutic drugs and/or devices may bedelivered to site of the occlusion via lumen 437.

Retrograde blood flow in vessel V is induced by placing venous returncatheter 52 of FIG. 3A into a remote vein, according to methodsdescribed hereinabove. The retrograde flow through lumen 437 inducesretrograde flow distal to occlusive element 436. Distal taper 440facilitates retrograde blood flow into lumen 437.

If antegrade flow is desired, inner sheath 434 may be retractedproximally to expose blood intake port 432, as shown in FIG. 14B. Thispermits antegrade flow to enter intake port 432 and continue flowing inan antegrade direction distal to occlusive element 436. Proximal taper438 is configured to enhance antegrade blood flow into intake port 432.

Cerebral flow manipulation may be enhanced by placing a first catheterin accordance with FIG. 14 in a common carotid artery and a secondcatheter in a vertebral artery, each on the hemisphere of the occlusion.FIG. 15 depicts apparatus suitable for controlling cerebral flow whenutilizing one carotid and one vertebral catheter in combination. In FIG.15, catheters 450 and 470 are configured to be disposed in the commoncarotid and vertebral arteries, respectively. However, it should beappreciated by those skilled in the art that two vertebral catheters maybe used, i.e., one in each of the vertebral arteries, in combinationwith the carotid catheter.

Catheters 450 and 470 each comprises a plurality of lumens. Innersheaths 456 and 476 are configured to slide longitudinally within anoutermost lumen of their respective catheters. Inner sheaths 456 and 476communicate with deployment knobs 452 and 472. Sliding deployment knobs452 and 472 within slots 454 and 474 controls movement of inner sheaths456 and 476, respectively.

Inflation ports 462 and 482 communicate with lumens of their respectivecatheters. Working lumens 458, 460, 478 and 480 provide each catheterwith two working lumens, e.g., for advancing guide wires andthrombectomy wires, and may be provided with hemostatic valves, forexample, Touhy-Borst connectors.

Biocompatible tubing 459 and 461 enable fluid communication betweenretrograde flow controller 465 and lumens of catheter 450 and 470,respectively. Retrograde flow controller 465 further communicates withvenous return line 52 of FIG. 3A via tubing 463. Switch 467 ofretrograde flow controller 465 permits tubing 459 and 461 to communicatewith retrograde flow of tubing 463 singularly or in combination, orswitch 467 may inhibit retrograde flow altogether. For example, whenretrograde flow is induced in tubing 463 via venous return line 52,either one of tubing 459 and 461, both, or neither may experienceretrograde flow based on the position of switch 467.

The apparatus described in FIG. 15 allow a physician to provide eitherretrograde, antegrade or hemostatic flow from two opposing cerebrallocations, i.e., the carotid and vertebral arteries. The lumens of thevertebral and/or carotid catheters may be perfused with blood or salineunder pressure to manipulate flow at selected cerebral locations. Theapparatus further allows for the injection of therapeutic drugs and/orthrombectomy devices. Chilled blood or saline may be delivered viaeither of the carotid and vertebral catheters to induce mild hypothermiaat selected cerebral locations, while drug agents may be used toselectively alter the pressure gradients.

Additionally, lytic agents may be delivered via either of the carotid orvertebral catheters to aid in the disintegration of the occlusion. Suchlytic agents preferably are used in combination with the flowmanipulation techniques in accordance with the present invention, todirect emboli resulting from the lytic process into the removalcatheter(s).

Referring to FIG. 16, method steps are described to manipulate cerebralflow in a variety of ways using a combination of carotid and vertebralcatheters. In FIG. 16A, a first catheter 500 comprising occlusiveelement 502 and blood intake port 504 is disposed in the left commoncarotid artery CCA. Inner sheath 506 is provided in a distalmostposition to prevent fluid from entering intake port 504, and occlusiveelement 502 is deployed to occlude antegrade flow. Balloon 508, e.g., asdescribed in FIG. 5, then is deployed in the ECA.

Similarly, a second catheter 520 comprising occlusive element 522 andblood intake port 524 is disposed in the left and/or right vertebralartery VA. In this example, one catheter is shown. Inner sheath 526 isprovided in a distalmost position to prevent fluid from entering intakeport 544, and occlusive element 522 is deployed to occlude antegradeflow.

Venous return line 52 of FIG. 3A then is placed in a remote vein,according to methods described hereinabove, and retrograde flow may beinduced either in the ICA, VA, or both arteries based on switch 467 ofFIG. 15. As depicted in FIG. 16A, switch 467 is set to a position thatpermits retrograde flow to be induced in both the carotid and vertebralcatheters.

At this time, any of the flow control devices described in FIG. 4optionally may be deployed to occlude flow in the opposing carotid andvertebral arteries, according to methods described hereinabove. In thisexample, this ensures that blood flow is controlled in the lefthemisphere.

The retrograde flow from catheters 500 and 520 encourages blood flowingin the middle cerebral artery MCA to flow toward both catheters, asindicated by the arrows in FIG. 16A. Thrombectomy wire 510 havingdeployable knot 512 then is advanced into the MCA via the ICA and snaresthrombus T, according to methods described hereinabove. Emboli Egenerated during the procedure are directed toward either one ofcatheters 500 and 520 for removal. Advantageously, the use of twocatheters in combination provides for improved aspiration of thetargeted vessel, in this case, the MCA.

Referring to FIG. 16B, deployable knob 472 of FIG. 15 is proximallyretracted to retract inner sheath 526 and expose intake port 524 ofcatheter 520. Switch 467 of retrograde flow controller 465 is positionedfor retrograde flow only through catheter 500. This allows antegradeflow in vertebral artery VA to enter intake port 524 and continueflowing in an antegrade direction into basilar artery BA and toward theMCA via the path indicated. The combination of antegrade flow from theleft VA and either antegrade or retrograde flow from the left ICAdirects emboli E generated in the MCA to flow primarily into catheter500.

There are several other variations possible for manipulating flow in thecerebral vasculature, to more efficiently deliver therapeutic drugsand/or direct emboli into a removal catheter. For example, therapeuticdrugs may be delivered to the MCA when switch 467 of FIG. 15 inhibitsvenous flow into both catheters 500 and 520, and each of blood intakeports 504 and 524 are closed. Therapeutic drugs may be delivered viaeither port 458 or 478 into the MCA, or mild hypothermia may be inducedby introducing chilled blood or saline.

It should be appreciated that varying the settings of retrograde flowcontroller 465 and deployable knobs 452 and 472 may provide for anycombination of antegrade, retrograde, or hemostatic flow in the carotidand vertebral arteries. There are too many flow combinations toillustrate, however, it is intended that therapeutic drugs, thrombectomydevices, cardioplegic and/or brain chilling agents may be deliveredunder a variety of controlled cerebral flow conditions. Additionally, aneuro guidewire and neuro catheter, as described in FIGS. 11 and 12Ahereinabove, may be used in conjunction with thrombectomy wire 510 ofFIG. 16.

While preferred illustrative embodiments of the invention are describedabove, it will be apparent to one skilled in the art that variouschanges and modifications may be made therein without departing from theinvention. The appended claims are intended to cover all such changesand modifications that fall within the true spirit and scope of theinvention.

1-25. (canceled)
 26. Apparatus suitable for manipulating cerebral bloodflow characteristics, the apparatus comprising: a catheter configuredfor introduction into a first blood vessel, having proximal and distalends, a lumen extending therebetween, and an occlusive element affixedto the distal end, the occlusive element having an opening thatcommunicates with the lumen, the occlusive element having a contractedposition suitable for transluminal insertion and an expanded positionwherein the occlusive element occludes antegrade flow in a vessel; andat least one flow control device adapted for introduction into a secondblood vessel, having proximal and distal ends and a flow control elementdisposed at the distal end; wherein when the occlusive element and flowcontrol device are deployed in the first and second blood vessels, theycontrol perfusion in a third blood vessel distal to the first and secondblood vessels.
 27. The apparatus of claim 26, further comprising athrombectomy wire configured to be advanced into the third blood vessel.28. The apparatus of claim 26, wherein the occlusive element comprisesan inflatable balloon.
 29. The apparatus of claim 28, wherein theinflatable balloon forms a tapered entrance to the lumen when theinflatable balloon is inflated.
 30. The apparatus of claim 26, whereinthe flow control element is an inflatable balloon.
 31. The apparatus ofclaim 26, wherein the third blood vessel is an MCA.
 32. The apparatus ofclaim 27, wherein the third blood vessel is an MCA.